Characterization of DIP1, a novel nuclear protein in Drosophila melanogaster Bruna De Felice, a, * Robert Roy Wilson, b Paolo Mondola, c Gianfranco Matrone, c Simona Damiano, c Corrado Garbi, d Luigi Nezi, d and Tin Tin Su e a Department of Life Sciences, University of Naples II, Via Vivaldi 43, 81100 Caserta, Italy b NOAA, 325 Broadway, Boulder, CO, USA c Department of Neuroscience, Section of Physiology, University of Naples “Federico II,” Naples, Italy d Department of Cellular and Molecular Biology and Pathology, University of Naples “Federico II,” Naples, Italy e MCD Biology 347 UCB, University of Colorado, Boulder 80309-0347, USA Received 2 June 2003 Abstract We have recently identified in Drosophila melanogaster a new gene encoding a nuclear protein, DIP1. Here we report the de- velopmental expression and the finding that DIP1 subcellular localization is in the nucleus and at the nuclear periphery during interphase in embryos. Interestingly, in humans, DIP1 antibody identified signals in nuclei from cultured cells and reacted with a rough 30 kDa protein in Western blotting experiments, demonstrating evolutionary conservation. Ó 2003 Elsevier Science (USA). All rights reserved. Keywords: Nuclear protein; Drosophila; Humans; Nuclear periphery protein The genomes of higher eukaryotes contain large amounts of simple and complex tandemly repeated DNA sequences, called satellite DNA. These are located primarily in centromeric heterochromatin. However, their role in possible functions of this region of the chromosome, such as chromosome pairing and segre- gation, is not very well understood yet. Dodeca satellite is a type of tandemly repeated DNA sequence that is located in the centromeric region of Drosophila mela- nogaster chromosome 3 and cross-hybridizes with DNA from other species including humans [1]. In human genome, dodeca satellite-like sequences were localized at the pericentromeric region of metaphase chromosome 9 and 15 and on the long arm of the Y chromosome. A homology between the dodeca-satellite consensus sequence and the human satellite 3 family se- quencehasbeenfound.Also, Drosophila dodeca sequence showed a zipper-like motif (GGGA) 2 similar to the human centromeric (TGGAA)n sequence [2]. In a previous work, using “one hybrid system assay” in yeast, we isolated a novel gene in D. melanogaster [3], using a double-strand dodeca-satellite sequence as a bait, encoding a protein, here renamed Dip1, of un- known function. The discovery of dodeca-satellite binding proteins could be biologically important, because they might be evolutionary conserved. Tounderstandtheroleofthisnovelproteinin D.m.,we studied the Dip1 gene expression pattern and subcellular localization from embryos during embryonic cycle. Because of conservation of dodeca satellite in human genome, we asked whether Drosophila DIP1 has ho- mologue proteins or a homologue protein domain in humans. Interestingly enough, in humans, DIP1 antibody also identified signals in nuclei from cultured cells and showed a rough 30 kDa protein in Western blotting experiments. Materials and methods Quantitative reverse transcription-PCR. Total RNAs (5 lg) were isolated from flies from 0–2 h old embryos, 2–24 h old embryo, larvae, Biochemical and Biophysical Research Communications 307 (2003) 224–228 www.elsevier.com/locate/ybbrc BBRC * Corresponding author. Fax: +39-823-274571. E-mail address: bruna.defelice@unina2.it (B. De Felice). 0006-291X/03/$ - see front matter Ó 2003 Elsevier Science (USA). All rights reserved. doi:10.1016/S0006-291X(03)01141-0